The present invention relates to an optical path adjusting system for adjusting an optical path of, for example, a laser beam so as to make the laser beam parallel to an optical axis of a condenser lens within the lens.
A laser oscillator, generally, is discharged at an internal electrode to excite a laser medium to thereby generate a laser beam. The laser beam is subjected to resonance amplification between at least a pair of mirrors. The amplified laser beam is transmitted through an output mirror and parallelly emitted therefrom to the outside. The parallel laser beam is reflected by a reflection mirror so as to change the direction thereof perpendicularly and passed through a condenser lens to irradiate a work so that fine working, for example, cutting, welding, or the like, can be performed upon the work. Accordingly, recently, a laser beam is used to perform working, for example, upon electronic parts. In performing working upon electronic parts with a laser beam, the laser beam is adjusted so that a set working position of a work is irradiated with the laser beam so as to perform working accurately.
However, the laser oscillator generates discharge heat due to discharge at the electrode. The temperature of the discharge heat varies in accordance with the degree of working on the work. In accordance with this change of temperature, there is a possibility that various parts of the laser oscillator, the reflection mirror, and so on slightly expand/contract so that the position of irradiation with the laser beam somewhat fluctuates to make it difficult to perform working accurately.
Accordingly, as a mechanism for adjusting the position of irradiation with the laser beam, there has been proposed a trimming apparatus as disclosed in Japanese Laid-Open Patent Publication (JP-A) No. 61-235091. This apparatus is provided with a reference light source, an optical system for inserting reference light emitted from the reference light source into a laser beam path so as to make the respectively optical paths of the reference light and the laser beam coincident with each other, a television camera for detecting the position of irradiation of the reference light as an image signal, and means for comparing actual positional data of the position of irradiation of the reference light with the previously programmed positional data of the position of irradiation of the laser beam so that an error obtained as a result of comparison is rapidly fedback to a deflection device to thereby automatically correct the position of irradiation of the reference light, and for outputting, at the same time, an error detection signal.
In such a configuration, the deflection device is operated so as to make the error zero with respect to the position of irradiation of the reference light. The deflection device is constructed in a manner so that a reflection mirror is attached to an output shaft of an electric motor and the electric motor is driven to rotate forward/backward to deflect the reflection mirror in the left/right direction so as to make the light coincident with the position of irradiation of the reference light. Generally, for example, if the deflection angle (operation angle) is "1", the deflection of light is "2". In other words, when the light is to be deflected by "1", the motor must rotate by the deflection angle of "0.5". Since the deflection angle of the motor is smaller than the deflection of the light, the deflection angle control mechanism must be arranged so as to perform fine angle adjustment with high accuracy. Accordingly, the deflection angle control mechanism is complicated in structure and difficult in operation. For example, when the deflection angle is displayed as an operation scale, it is impossible to enlarge the scale intervals, and it is somewhat difficult to read the scale. Thus, the device is not convenient in operation.